Timing device for stethoscopes



March 27, 1951 FALK 2,546,890

TIMING DEVICE FOR STETHOSCOPES Filed March 13, 1950 36 A n 0 fa 4 Inventor 7/ hi 7, 38 30 lrwn A. Fa/lr E I WWW Patented Mar. 27, 1951 UNITED STATES PATENT- 2,546,890 riMiNo DEVICE FOR srE'rHosooPEs Irvin A. Falk, San Francisco, Calif. Application March 13, 1950, Serial No. 149,426 I 7 3 Claims. 1

This invention relates to new and useful improvements and structural refinements in stethoscopes, and the principal object of the invention is to issue, at the termination of a predetermined interval of time, an audible signal to a physician who, in the interim, has been counting a patients heart beat, this being so arranged that although being audible to the physician, the signal is not audible to the patient, whereby the heart beat counting procedure may be undertaken without the patients knowledge.

The above object is carried out by embodying in one earphone of the stethoscope a combined timing and signal issuing device which may be conveniently and inconspicuously energized bythe physician at an appropriate moment, an in portant feature of the invention residing in the provision of means for energization or actuation of the device and the issuance of a signal, thereby marking the termination of the counting period.

Some of the advantages of the invention reside in its simplicity of construction, in its efiicient, dependable and inconspicuous operation and in its adaptability for embodiment in earphones of stethoscopes of different types.

With the above more important objects and features in view, and such other objects and features as may be come apparent as this specification proceeds, the invention consists essentially of the arrangement and construction of parts as Figure 3 is a sectional view, taken substantiallyin the plane of the line 33 in Figure 4;

Figure 4 is a sectional view, taken substantially in the plane of the line 4-4 in Figure 3; and

Figure 5 is a horizontal sectional view of a piston used in the invention.

Like characters of reference are employed to designate like parts in the specification and throughout the several views.

Referring now to the accompanying drawings in detail, the general reference character It] designates one of the earphones of a conventional stethoscope, this earphone including in its construction a circular housing i2 provided with a removable cover M, the latter serving to sustain in position a sound reproducing diaphragm l6 which is disposed immediately adjacent an undulated. disk-shaped member [8. A tube 2'3 extends axially in the housing [2 and is connected at one end thereof to the member l8 in the conventional, well known .manner,-the remaining end of this tube projecting outwardly from the housing and being in communication with an ex:-

tension nipple 22 for connection to a flexible, sound-transmitting tube of the stethoscope (the latter tube not being illustrated in the accompanying drawings).

The invention, which is designated generally by the reference character 24, consists of a-combined signaling and timing unit which is disposed in the earphone housing l2 and includes in its construction a body 26 affording a cylinder 28 having closed ends 30, the body being provided with a by-pass 32 extending from one end of the cylinder 28 to the other.

In addition, the body 26 is provided with a pair of vent passages 34 which are spaced inwardly from the ends and communicate with the cylinder 28, while a piston 35 is reciproeable in the cylinder and is provided in opposite end portions with L-shaped vent passages 36 which are registrable with the passages 34, as will be hereinafter more fully explained.

An adjusting screw 46 is provided in the body 26 and extends into the icy-pass 32 so as to regulate the rate of flow of fluid such as air through the by-pass, the adjusting screw 66 being accessible through an opening or aperture 42 formed in the housing [2. v

The means for reciprocating the piston tficonsists of a rocker 44 which is swingably mounted on the aforementioned tube 20 and is provided with a flat platform 48 and with a depending arm 48 which has a bifurcated lower end portion or fork 50 in operative engagement with a lug or detent 52 on an L-shaped slide 5 3. The latter is slidably mounted on the body 26 and is secured to the piston 38 by a screw 56 which extends into the cylinder 28 through a slot 58 in the body26, it being apparent from the foregoing that when the rocker 44 is oscillated as indicated by the arrow 60 in Figure 4, the piston 36 will be slid from one side of the cylinder 28 to the other.

The means for oscillating the rocker 33 consists of an actuating member 62 which is pivotally mounted on a fulcrum B4 in the housing 52 and is formed integrally with two finger-pieces 5 6 which project outwardly from the housing, substantially as shown. The member 62 is provided with a socket 68 for a spherical pressure-ez-i rting element 10 which is pressed by a compression spring 12, disposed in the socket E8, in rolling engagement with the platform Q6 of the rocker'M.

The actuating element 62 is, of course, adapted for oscillation from one side to'the other, the limits of its oscillating movement being'set by -a pair of stops M which are affixed to the member 62 and are engageable with the inner wall of the housing [2, as Figure 2:

Having thus described the constructionrof;the

will be clearly apparent from.

3 invention, the operation thereof will now be explained.

Assuming the device to be in the position shown in Figures 2 and 4, with the actuating member 62 swung to the left and the element l9 engaging the right-hand portion of the rocker platform 46, finger pressure applied to the right fingerpiece in the direction of the arrow 76 will swing the member 62 to the right and, assuming the rocker 44 to be temporarily immovable, the spherical element It will roll upwardly along the inclined platform 46, thus compressing the spring 12.

However, when the spring is compressed, the resiliency thereof will be sufficient to overcome the resistance created by a volume of air confined in the right-hand end portion of the cylinder 28, it being understood that until this moment the piston 36 was disposed in the left-hand side of the cylinder and the right-hand vent passage 3a in the body 26 was covered by the piston so that air confined in the right-hand portion of the cylinder could not escape except through the by-pass 32. This by-pass, being of a relatively small diameter, functions in the nature of a metering orifice which permits the'flow of air therethrough only at a predetermined, slow rate, thus creating a resistance against the sliding movement of the piston 36 and permitting the piston to slide, at a similarly slow rate, under themfiuence of pressure exerted by the spring-pressed element [2 on the rocker platform id.

However, the piston 36 will ultimately slide to the right to a suflicient extent that the righthand passage 38 of the piston is in register with the right-hand passage 34 of the body 26, thus facilitating instantaneous release of air pressure from the right-hand side of the cylinder into the atmosphere, and permitting the right-hand end of the piston to strike or impact the right-hand end 30 of the cylinder 23, thus creating an audible signal.

The interval of time between the depression of the actuating member 62 and the issuance of the audible signal may be varied by turning the adjusting screw 4%) so as to regulate the rate of flow of air through the by-pass 32, and this interval of time, perhaps seconds or so, is to be utilized by the physician in counting the heart beat of his patient, without the latter necessarily knowing that the physician is so doing, since the issued signal is audible only to the physician and not the patient.

Theforegoing completes one cycle of operation of the invention, the next cycle becoming effective when the actuating member 62 is swung in the direction of the arrow F8 so as to eventually cause the piston 36 to slide to the left, ultimately resulting in the issuance of an audible signal, arising from the impact of the left end of the piston against the left end wall of the cylinder.

It is believed that the advantages and use of the invention will be clearly apparent from the foregoing disclosure and accordingly, further description thereof at this point is deemed unnecessary.

While in the foregoing there has been shown and described the preferred embodiment of this invention it is to be understood that minor changes in the details of construction, combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as claimed.

Having described the invention, what is claimed as new is:

1. In a stethoscope, the combination of a sound receiver including a housing and a diaphragm therein, a cylinder mounted in said housing and having closed end walls, a piston slidable in the cylinder from one end wall to the other, said cylinder having a by-pass extending between its opposite ends whereby fluid at one side of said piston may be transferred at a predetermined rate to the other side when the piston is in motion, and means for sliding said piston, said piston and said cylinder being provided with registerablevent passages whereby fluid inthe cylinder under pressure of said piston may be released at a predetermined point to permit the piston to impact an end wall of the cylinder and issue an audible signal, and means for regulating the rate of passage of fluid through said by-pass.

2. In a stethoscope, the combination of a sound receiver including a housing and a diaphragm therein, a cylinder mounted in said housing and having closed end walls, a piston slidable in the cylinder from one end wall to the other, said cylinder having a by-pass extending between its opposite ends whereby fluid at one side of said piston may be transferred at a predetermined rate to the other side when the piston is in motion, and means for sliding said piston, said piston and said cylinder being provided with registerabie vent passages whereby fluid in the cylinder under pressure of said piston may be released at a predetermined point to permit the piston to impact an end wall of the cylinder and issue an audible signal, said means for sliding said piston comprising an oscillatory actuating member pivotally mounted in said housing and projecting outwardly therefrom, a rocker fulcrumed in the housing and operatively connected to said piston, a pressure exerting element provided on said actuating member, and resilient means urging said element in engagement with said rocker whereby pressure may be exerted on said piston when the actuating element is swung from one side to the other.

in a stethoscope, the combination of a sound receiver including a housing and a diaphragm therein, a cylinder mounted in said housing and having closed end walls, a piston slidable in the cylinder from one end wall to the other, said cylinder having a by-pass extending between its opposite ends whereby fluid at one side of say piston may be transferred at a predetermined rate to the other side when the piston is in motion, and means for sliding said piston, said piston and said cylinder being provided with registerable vent passages whereby fluid in the cylinder under pressure of said piston may be released at a predetermined point to permit the piston to impact an end wall of the cylinder and issue an audible signal.

IRVIN A. FALK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,694,059 Denny Dec. 4., 1928 1,767,242 Kiefer June 24, 1930 1,846,231 Susman Feb. 23, 1932 2,032,189 stilling Feb. 25, 1936 2,042,761 Bennett June 2, 1936 2,377,461 Swift June 5, 1945 

